Manufacturing method of liquid crystal display device

Abstract

It is an object of the present invention to suppress light leakage in a dark state which is generated by rubbing treatment. A liquid crystal material containing an ultraviolet curable liquid crystalline monomer at a concentration of more than 0 wt % and not more than 1.0 wt % is used for a liquid crystal layer, and the liquid crystal layer is irradiated with ultraviolet rays. By applying such a liquid crystal layer to a liquid crystal display device, light leakage in a dark state can be suppressed, and the black display can be improved. Therefore, a liquid crystal display device with an excellent contrast and high display quality can be obtained.

What is claimed is: 
     
       1. A method for manufacturing a liquid crystal display device, comprising the steps of:
 forming an electrode over one surface of each of a pair of substrates; 
 forming orientation films over the electrodes, respectively; and 
 sandwiching a liquid crystal layer by the pair of substrates so that the orientation films face each other, 
 wherein the liquid crystal layer includes a liquid crystal molecule and an ultraviolet curable liquid crystalline monomer; 
 wherein the liquid crystal layer is irradiated with ultraviolet rays so that the ultraviolet curable liquid crystalline monomer reacts; 
 wherein a part of the reacted ultraviolet curable liquid crystalline monomer is in contact with the orientation films, and 
 wherein the liquid crystal molecule is oriented vertical to the substrate so that a pre-tilt is suppressed. 
 
     
     
       2. The method for manufacturing a liquid crystal display device according to  claim 1 , further comprising the step of:
 performing orientation treatment on at least one of the orientation films. 
 
     
     
       3. The method for manufacturing a liquid crystal display device according to  claim 2 ,
 wherein the orientation treatment is a rubbing method. 
 
     
     
       4. The method for manufacturing a liquid crystal display device according to  claim 1 , further comprising the step of:
 placing a pair of polarizing plates of which polarizing axes cross at right angles over the pair of substrates. 
 
     
     
       5. The method for manufacturing a liquid crystal display device according to  claim 1 ,
 wherein the ultraviolet curable liquid crystalline monomer is an acryloyloxy group attached with a liquid crystal skeleton. 
 
     
     
       6. The method for manufacturing a liquid crystal display device according to  claim 5 ,
 wherein the liquid crystal skeleton is one of a biphenyl-based skeleton, a tolan-based skeleton, an ester-based skeleton, an alkenyl-based skeleton, a cyclohexene-based skeleton, an azine-based skeleton, a fluorine-containing condensed ring-based skeleton, and a naphthalene-based skeleton. 
 
     
     
       7. A method for manufacturing a liquid crystal display device, comprising the steps of:
 forming an electrode over one surface of each of a pair of substrates; 
 forming orientation films over the electrodes, respectively; and 
 sandwiching a liquid crystal layer by the pair of substrates so that the orientation films face each other, 
 wherein the liquid crystal layer includes a liquid crystal molecule, and an ultraviolet curable liquid crystalline monomer at a concentration of more than 0 wt % and not more than 5.0 wt %; 
 wherein the liquid crystal layer is irradiated with ultraviolet rays so that the ultraviolet curable liquid crystalline monomer reacts; 
 wherein a part of the reacted ultraviolet curable liquid crystalline monomer is in contact with the orientation films, and 
 wherein the liquid crystal molecule is oriented vertical to the substrate so that a pre-tilt is suppressed. 
 
     
     
       8. The method for manufacturing a liquid crystal display device according to  claim 7 , further comprising the step of:
 performing orientation treatment on at least one of the orientation films. 
 
     
     
       9. The method for manufacturing a liquid crystal display device according to  claim 8 ,
 wherein the orientation treatment is a rubbing method. 
 
     
     
       10. The method for manufacturing a liquid crystal display device according to  claim 7 , further comprising the step of:
 placing a pair of polarizing plates of which polarizing axes cross at right angles over the pair of substrates. 
 
     
     
       11. The method for manufacturing a liquid crystal display device according to  claim 7 ,
 wherein the ultraviolet curable liquid crystalline monomer is an acryloyloxy group attached with a liquid crystal skeleton. 
 
     
     
       12. The method for manufacturing a liquid crystal display device according to  claim 11 ,
 wherein the liquid crystal skeleton is one of a biphenyl-based skeleton, a tolan-based skeleton, an ester-based skeleton, an alkenyl-based skeleton, a cyclohexene-based skeleton, an azine-based skeleton, a fluorine-containing condensed ring-based skeleton, and a naphthalene-based skeleton. 
 
     
     
       13. A liquid crystal display device comprising:
 a pair of electrodes between a pair of substrates; 
 a pair of orientation films between the pair of electrodes; and 
 a liquid crystal layer interposed between the pair of orientation films, 
 wherein the liquid crystal layer includes a liquid crystal molecule, and an ultraviolet curable liquid crystalline monomer; 
 wherein the liquid crystal layer is irradiated with ultraviolet rays so that the ultraviolet curable liquid crystalline monomer reacts; 
 wherein a part of the reacted ultraviolet curable liquid crystalline monomer is in contact with a respective one of the pair of orientation films, and 
 wherein the liquid crystal molecule is oriented vertical to the substrate so that a pre-tilt is suppressed. 
 
     
     
       14. The liquid crystal display device according to  claim 13 ,
 wherein orientation treatment is given to the pair of orientation films. 
 
     
     
       15. The liquid crystal display device according to  claim 14 ,
 wherein the orientation treatment is a rubbing treatment. 
 
     
     
       16. The liquid crystal display device according to  claim 13 , further comprising:
 a pair of polarizing plates of which polarizing axes cross at right angles which are placed over the pair of substrates. 
 
     
     
       17. The liquid crystal display device according to  claim 13 ,
 wherein the ultraviolet curable liquid crystalline monomer is an acryloyloxy group attached with a liquid crystal skeleton. 
 
     
     
       18. The liquid crystal display device according to  claim 17 ,
 wherein the liquid crystal skeleton is one of a biphenyl-based skeleton, a tolan-based skeleton, an ester-based skeleton, an alkenyl-based skeleton, a cyclohexene-based skeleton, an azine-based skeleton, a fluorine-containing condensed ring-based skeleton, and a naphthalene-based skeleton. 
 
     
     
       19. The liquid crystal display device according to  claim 13 , further comprising:
 a projection over at least one of the pair of electrodes. 
 
     
     
       20. The liquid crystal display device according to  claim 19 ,
 wherein the projection is covered with one of the pair of orientation films. 
 
     
     
       21. The liquid crystal display device according to  claim 19 ,
 wherein a material of the projection is selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, an acrylic resin, an epoxy resin, a resist, and divinylbenzene. 
 
     
     
       22. A liquid crystal display device comprising:
 a pair of electrodes between a pair of substrates, respectively; 
 a pair of orientation films between the pair of electrodes, respectively; and 
 a liquid crystal layer interposed between the pair of orientation films, 
 wherein the liquid crystal layer includes a liquid crystal molecule, and an ultraviolet curable liquid crystalline monomer at a concentration of more than 0 wt % and not more than 5.0 wt %; 
 wherein the liquid crystal layer is irradiated with ultraviolet rays so that the ultraviolet curable liquid crystalline monomer reacts; 
 wherein a part of the reacted ultraviolet curable liquid crystalline monomer is in contact with a respective one of the pair of orientation films, and 
 wherein the liquid crystal molecule is oriented vertical to the substrate so that a pre-tilt is suppressed. 
 
     
     
       23. The liquid crystal display device according to  claim 22 ,
 wherein orientation treatment is given to the pair of orientation films. 
 
     
     
       24. The liquid crystal display device according to  claim 23 ,
 wherein the orientation treatment is a rubbing treatment. 
 
     
     
       25. The liquid crystal display device according to  claim 22 , further comprising:
 a pair of polarizing plates of which polarizing axes cross at right angles which are placed over the pair of substrates. 
 
     
     
       26. The liquid crystal display device according to  claim 22 ,
 wherein the ultraviolet curable liquid crystalline monomer is an acryloyloxy group attached with a liquid crystal skeleton. 
 
     
     
       27. The liquid crystal display device according to  claim 26 ,
 wherein the liquid crystal skeleton is one of a biphenyl-based skeleton, a tolan-based skeleton, an ester-based skeleton, an alkenyl-based skeleton, a cyclohexene-based skeleton, an azine-based skeleton, a fluorine-containing condensed ring-based skeleton, and a naphthalene-based skeleton. 
 
     
     
       28. The liquid crystal display device according to  claim 22 , further comprising:
 a projection over at least one of the pair of electrodes. 
 
     
     
       29. The liquid crystal display device according to  claim 28 ,
 wherein the projection is covered with one of the pair of orientation films. 
 
     
     
       30. The liquid crystal display device according to  claim 28 ,
 wherein a material of the projection is selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, an acrylic resin, an epoxy resin, a resist, and divinylbenzene. 
 
     
     
       31. The method for manufacturing a liquid crystal display device according to  claim 1 , further comprising the step of:
 forming a projection over at least one of the electrodes. 
 
     
     
       32. The method for manufacturing a liquid crystal display device according to  claim 31 , wherein the projection is covered with one of the orientation films. 
     
     
       33. The method for manufacturing a liquid crystal display device according to  claim 31 , wherein a material of the projection is selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, an acrylic resin, an epoxy resin, a resist, and divinylbenzene. 
     
     
       34. The method for manufacturing a liquid crystal display device according to  claim 7 , further comprising the step of:
 forming a projection over at least one of the electrodes. 
 
     
     
       35. The method for manufacturing a liquid crystal display device according to  claim 34 , wherein the projection is covered with one of the orientation films. 
     
     
       36. The method for manufacturing a liquid crystal display device according to  claim 34 , wherein a material of the projection is selected from the group consisting of silicon oxide, silicon nitride, silicon oxynitride, an acrylic resin, an epoxy resin, a resist, and divinylbenzene.